On Fri, 08 Mar 2024 10:31:28 -0300 James Almer <jamr...@gmail.com> wrote: > On 3/8/2024 10:21 AM, Niklas Haas wrote: > > From: Niklas Haas <g...@haasn.dev> > > > > Implementation copied wholesale from dav1d, sans SIMD, under permissive > > license. This implementation was extensively verified to be bit-exact, > > so it serves as a much better starting point than trying to re-engineer > > this from scratch for no reason. (I also authored the original > > implementation in dav1d, so any "clean room" implementation would end up > > looking much the same, anyway) > > > > The notable changes I had to make while adapting this from the dav1d > > code-base to the FFmpeg codebase include: > > > > - reordering variable declarations to avoid triggering warnings > > - replacing several inline helpers by avutil equivalents > > - changing code that accesses frame metadata > > - replacing raw plane copying logic by av_image_copy_plane > > > > Apart from this, the implementation is basically unmodified. > > Do we want this to be public? Both as a struct and the decoding functions. > It could be used by libavfilter or even outside our libraries. The hevc > decoder would export the relevant T.35 SEI in the new struct if told to > not apply fg, like we already do in av1.
I'm not sure if the AFGS1 struct itself needs to be public, since it is largely just a codec-internal wrapper for multiple param sets (for scalable codecs). If we want to add a public film grain synthesis helper, IMHO it should be a wrapper around both ff_aom_apply_film_grain *and* ff_h274_apply_film_grain, which directly ingests an AVFilmGrainParams and resolves to the correct implementation. So we can merge this series as-is and still add a public helper on top. Incidentally, there is a strong precedent here: dav1d.h exports dav1d_apply_grain() precisely for the reason that VLC needs to initialize the decoder *before* it knows whether to apply synthesis on GPU or CPU, so it has to set the equivalent of `-export_side_data film_grain` at init time and manually apply CPU film grain synthesis if it turns out that GPU fgs is unavailable. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
